In the set of consecutive integers from 21 to 46 , inclusive, there are 2 integers that are multiples of both 2 and 7. How many integers in the set are mulitples of neither 2 nor 7 ?.

The answer is 11 but
Please show me how to do it

The sum of two numbers is 86, and their difference is 20. find the two numbers

It says factor each expression 49x-28?

Frank has a devised a formula for his catering business that calculates the number of meatballs he needs to prepare. the formula is m=4a+2c, where c=number of children; m=number of meatballs; a=number of adults. how many meatballs are required for a party of 10 adults and 5 children?